英国学生科学读本 第94期:一副风箱(2)

 　　for when you shut the bellows¹, the valve cannot close the air-hole because of your finger, 因为, 当你关闭风箱把手时, 你的手指使得阀门无法关闭空气进出的圆孔,

　　and most of the air then escapes through this hole instead of going out through the nozzle. 那么大部分空气也就通过这个孔逃了出去而不是通过喷嘴透出。

　　Every one knows that we use the bellows to make the fire burn more brightly. 大家都知道, 我们使用风箱来增强火焰的燃烧。

　　But how do they do this? 然而, 这其中的原理是什么呢?

　　It is by causing more air to pass among the hot coals. 因为我们促使更多的空气穿过了炙热的火炭。

　　Air is a mixture of several gases, and one of these gases—oxygen —is necessary for making the coals burn. 空气是一种混合气体, 而这其中的氧气则是煤炭燃烧的关键所在。

　　If your mother has no bellows, what does she do when she wants the fire to burn more brightly ? 如果你的母亲没有风箱, 那么当她希望让火焰更旺时会怎么做呢?

　　She opens either the door or the window, to let more air into the room, 她会打开门或者窗户, 使得房间中的空气更加充沛；

　　or she stirs the fire with the poker², to let the air pass freely among the coals. 或者, 她会使用拨火棍来搅动火堆, 促使空气能够大量穿过火炭。

　　Have you ever watched a blacksmith working at his forge? 你有没有看到过铁匠在锻造工厂的工作情景?

　　He needs a very hot fire to heat the iron bars which he makes into horse-shoes and many other things; and he could not have this without using bellows. 要制造马蹄铁或者其他诸多铁制产品, 需要极为炎热的火焰来加热铁条, 而风箱就必不可少。

　　If you look carefully, you will see that there is a difference between the bellows of the blacksmith's forge and those which you use for your kitchen fire. 如果你仔细观察的话, 就会发现, 锻造工厂所用的风箱与你家厨房里的有所不同。

　　The air comes out of your kitchen bellows in puffs⁴, but it comes out of the blacksmith's bellows in a steady stream. 厨房风箱吹出的风一阵一阵, 而铁匠的风箱却能持续不断地吹出风来。

　　If we were to take a common pair of bellows, and hinge the lower board of another pair to their under side, 如果我们拿起一副日常家用的风箱, 将它上方的木片与另一幅风箱的下方木片固定在一起，

　　in the same way as the two boards are hinged together, we should then have bellows somewhat like those of the blacksmith. 就好似一副风箱中两块木片的固定方式一样——就可以得到一个类似于铁匠使用的风箱了。

　　The middle board is fixed⁵; the under board is worked by a handle; and the top board is free to rise when air is forced in.  中间的木片固定不动；下方的木片通过把手进行移动, 而上方的木片则能够在空气流入时自由抬起。

　　When the blacksmith works his bellows, air is sent from the lower chamber⁶ into the upper chamber in puffs, 当铁匠使用风箱时, 空气通过下气室一阵一阵地进入上气室；

　　and is then driven out through the nozzle by the weight of the uppermost board. 然后, 在最上层木片的重力作用下通过喷嘴透出。

　　But air can be sent in through the valve faster than it can escape through the nozzle, 然而, 通过阀门流入的空气比喷嘴流出的空气数量更多,

　　and before the first puff³ is forced out, more air has been received from the chamber below.  当第一阵空气尚未透出时, 下气室又送来了更多空气。

　　Thus there is a steady stream of air sent through the fire, instead of a series of puffs. 结果, 燃烧的火焰就能不停地得到新鲜空气。

1 bellows   

n.风箱；发出吼叫声，咆哮（尤指因痛苦）( bellow的名词复数 )；（愤怒地）说出（某事），大叫v.发出吼叫声，咆哮（尤指因痛苦）( bellow的第三人称单数 )；（愤怒地）说出（某事），大叫

参考例句：

• His job is to blow the bellows for the blacksmith. 他的工作是给铁匠拉风箱。 来自辞典例句
• You could, I suppose, compare me to a blacksmith's bellows. 我想，你可能把我比作铁匠的风箱。 来自辞典例句

2 poker   

n.扑克；vt.烙制

参考例句：

• He was cleared out in the poker game.他打扑克牌，把钱都输光了。
• I'm old enough to play poker and do something with it.我打扑克是老手了，可以玩些花样。

3 puff   

n.一口(气)；一阵(风)；v.喷气，喘气

参考例句：

• He took a puff at his cigarette.他吸了一口香烟。
• They tried their best to puff the book they published.他们尽力吹捧他们出版的书。

4 puffs   

n.吸( puff的名词复数 )；（烟斗或香烟的）一吸；一缕（烟、蒸汽等）；（呼吸或风的）呼v.使喷出( puff的第三人称单数 )；喷着汽（或烟）移动；吹嘘；吹捧

参考例句：

• We sat exchanging puffs from that wild pipe of his. 我们坐在那里，轮番抽着他那支野里野气的烟斗。 来自辞典例句
• Puffs of steam and smoke came from the engine. 一股股蒸汽和烟雾从那火车头里冒出来。 来自辞典例句

5 fixed   

adj.固定的，不变的，准备好的；(计算机)固定的

参考例句：

• Have you two fixed on a date for the wedding yet?你们俩选定婚期了吗？
• Once the aim is fixed,we should not change it arbitrarily.目标一旦确定，我们就不应该随意改变。

6 chamber   

n.房间，寝室；会议厅；议院；会所

参考例句：

• For many,the dentist's surgery remains a torture chamber.对许多人来说，牙医的治疗室一直是间受刑室。
• The chamber was ablaze with light.会议厅里灯火辉煌。